Question: $ { {5} \times \left[\begin{array}{rrr}{-2} & {4} & {2} \\ {4} & {-1} & {-2}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{5}\times{-2} & {5}\times{4} & {5}\times{2} \\ {5}\times{4} & {5}\times{-1} & {5}\times{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-10} & {20} & {10} \\ {20} & {-5} & {-10}\end{array}\right]}$